Firearm ventilated sight rib with a dovetail key



H. A. INTO March 2, 1965 FIREARM VENTILATED SIGHT RIB WITH A 'DOVETAIL KEY Filed June 12, 1963 INVENTOR. HENRY/4.]NTO

ATTORNE United States Patent .0

3,171,226 FIREARM VENTILATED SIGHT RIB WITH A DQVETAIL KEY Henry A. Into, Wallingford, Conn, assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed June 12, 1963, Ser. No. 287,316 6 Claims. (Cl. 42-76) This invention relates to sight ribs for shotguns and the like.

This invention more specifically relates to a floating ventilated sight rib adapted to be mounted on a shotgun barrel or the like in a simple and economical manner.

Ventilated sight ribs for shotguns and the like are Well known in the art. The object of providing a ventilated sight rib is to overcome the detrimental eifects on sighting a shotgun caused by heat waves rising from the heated barrel and interfering with the line of sight. A ventilated rib interrupts the heat waves from the barrel and is itself maintained cool by air circulating around the rib.

One of the problems encountered in securing a ventilated sight rib to a gun barrel arises due to the unequal heating of the barrel and the rib and therefore the different degrees of expansion of these elements. If the rib is rigidly secured to the barrel along its length, there is a tendency for the rib to stretch due to unequal heating and cause a curvature itself detrimental to the proper sighting of the firearm. It is therefore desirable that the sight rib be mounted on the barrel in such a manner that the sight rib and the barrel can expand independently with no adverse effect such as mentioned above. To provide for such a mounting arrangement, it is desirable that the rib be rigidly attached to the gun barrel at only a single point and slidably carried by the barrel along the rest of its length. Prior art devices are known in which such a single point of rigid attachment is used to mount a sight rib on a gun barrel. The prior art structures normally provide a pin or screw which is passed through the rib and threaded into one of the mounting posts for the rib which is in turn rigidly attached to the barrel. Such an arrangement is shown in US. Patent No. 2,620,583 issued to Simmons. This arrangement introduces another prob lem since the diameter of the pin which can be used in such an arrangement is limited by practical considerations. There is therefore a tendency for the pin to be sheared off due to the mass of the sight rib being accelerated by the recoil of the firearm as it is fired. To overcome these deficiencies, a depending lug has been rigidly secured to the sight rib and made to interlock behind another lug rigidly attached to the barrel to absorb the recoil shock. Such an arrangement is shown in US. Patent No. 2,669,052 issued to Simmons. While this provides a satisfactory arrangement for relieving shear stresses on the mounting pin, it introduces additional expense in both the fabricating and mounting operation.

It is a feature of this invention to provide a sight rib and mounting for shotguns or the like which overcomes the deficiencies of the prior art and which is simple and economical to fabricate and install.

According to this invention, a sight rib is provided with a longitudinal female groove of dovetail cross section extending along its entire length. The female dovetail groove is of equal cross section throughout its entire length to facilitate manufacturing and to reduce cost. A plurality of support posts having male projections of dovetail cross section are secured to the gun barrel and adapted to interlock with the female dovetail groove on the sight rib which is slid onto the posts. The support posts mount the rib in spaced relation relative to the barrel. Intermediate the ends of the barrel, an anchor post is rigidly attached to the barrel. The anchor post includes a pair of integral male dovetail projections separated by a female recess of dovetail cross section extending transversely of the anchor post. The pair of male dovetail projections on the anchor post engage and support the sight rib in the same manner as the support posts referred to above. The sight rib is further provided with a transverse female recess of dovetail cross section which is directly aligned iwth the transverse recess in the anchor post when the sight rib is in proper mounted position on the barrel. A male key of double dovetail cross section is then inserted in the aligned transverse recesses in the mounting post and sight rib to lock the sight rib against longitudinal movement relative to the barrel. The key has sufiicient bearing and cross sectional area to absorb all impact forces on the sight rib which occur when the gun is fired. These forces are distributed uniformly through the relatively wide bearing areas of the key. A pin which may be in the form of a middle sight interlocks the sight rib when the key to prevent inadvertent transverse movement of the key relative to the sight rib. The pin is passed through the sight rib and secured in the key by screw threads or the like. It is readily apparent that there are no forces transmitted to this pin which would have a tendency to shear the pin. All impact forces are transmitted to the key itself.

Another advantage of this system is that the simple dovetail cross section in all interlocking elements is readily machinable with great accuracy. It is therefore possible to obtain a tight mating fit of all parts in the mounting system, thereby minimizing the shear forces caused by acceleration of the rib during recoil.

This invention will now be described in detail with reference to the accompanying drawings in which:

FIGURE 1 is a side View showing the sight rib of this invention mounted on the barrel of a firearm.

FIGURE 2 is a perspective view showing the details of the rib prior to assembly.

FIGURE 3 is a perspective view showing the details of the rib in assembled condition on a gun barrel.

Referring now to the drawings, a barrel 1 is shown mounted on the receiver 2 of a firearm. A plurality of support posts 3 are rigidly secured to the barrel by soldering, brazing or other equivalent means. Each of the support posts is provided with an integral male projection 4 of dovetail cross section as clearly seen in FIGURE 2. Mounted on the barrel 1 intermediate the ends thereof is an anchor post generally indicated 5. The anchor post 5 is preferably provided with a pair of male projections 6 and 7 of dovetail cross sectional configuration. Formed in the anchor post intermediate the projections 6 and 7 is a female recess 8 having a dovetail cross sectional configuration.

A sight rib 9 is slidably mounted on said support posts 3 and anchor post 5. Sight rib 9 is provided with a emale groove iii of dovetail cross section which extends the entire length of said rib. Female dovetail groove 10 interlocks with male dovetail projections 6 and 7 on anchor post 5 and projections 4 on support posts 3 to mount said rib for longitudinal sliding movement relative to the barrel 1.

A transverse female recess 11 is formed in the sight rib 9 which is vertically aligned with transverse recess 8 in the anchor post 5 when the sight rib 9 is in proper mounted position on the barrel 1. Recess 11 also has a dovetail cross section so that when recesses 8 and 11 are aligned, a combined female opening is formed in the sight rib and anchor post which is essentially of double dovetail cross section as clearly seen in FIGURE 3.

Sight rib 9 is locked against longitudinal movement relative to barrel 1 at a single point so that the remainder of the rib is slidably carried by the barrel along the remainder of its length. This arrangement allows the rib to expand :and contract at a different rate than the barrel as the barrel is heated during firing of the firearm. To lock the rib, 9 against longitudinal movement relative to the barrel, a key 12 of double dovetail cross sectional configuration is inserted into the opening formed by transverse recesses 8 and 11. Key 12, as is apparent from the drawings, provides a relatively large bearing area to transmit the forces of recoil uniformly from the rib to the barrel as the firearm is fired.

In order to securely hold key 12 in position in the transverse recesses 8 and 11, a pin 13 is passed through an opening 14 in rib 9 and screw-threadedly engaged in opening 15 in key 12. Pin 13 may be an ordinary screw or it may take the form of a middle sight as shown in the drawings. It is readily apparent that there are no shear forces acting on pin 13 which has the primary function of retaining male key 12 in the female recesses 3 and 11.

While the transverse recesses 8 and 11 are preferably formed of dovetail cross sectional configuration and the key 12 has a corresponding configuration; it is apparent that these configurations could be made generally rectangular and perform the function of locking the rib against longitudinal movement. The principal advantage of the dovetail configuration, however, is that it functions to lock the rib at the point of rigid connection to the barrel against movement vertically away from the barrel as well as holding against longitudinal movement of the rib. This consideration is even more significant if it is found desirable to eliminate one or both of the projections 6 and 7 from the anchor post.

While this invention has been described in detail with reference to a preferred embodiment illustrated in the drawings, all variations in design and structural detail are contemplated which are within the spirit and scope of the appended claims.

I claim:

1. In a firearm including a barrel, a plurality of support posts rigidly secured to said barrel at longitudinally spaced intervals, a sight rib mounted on said support posts for longitudinal slidable movement relative to said barrel, an anchor post rigidly secured to said barrel intermediate the ends of said barrel, said anchor post having a first recess extending transversely of said barrel, a corresponding second recess formed in said sight rib in aligned relationship with the recess in said anchor post and extending transversely of said barrel, a key mounted in said recesses to securely lock said sight rib against relative movement longitudinally of said barrel, pin means extending through said sight rib and into said key to lock said key securely in said recesses, said key extending substantially across the width of said rib to provide a maximum bearing surface to absorb longitudinal recoil forces transmitted from the barrel to said rib.

Al r.

2. The firearm of claim 1 in which each of said support posts has formed integral therewith a projecting portion of dovetail cross section adapted to interlock with a groove of dovetail cross section which extends the entire length of said sight rib.

3. The firearm of claim 2 in which said anchor post includes a pair of projections of dovetail cross section adapted to interlock with said groove in said sight rib and in which said first recess is formed between said pair of projections.

4. The firearm of claim 3 in which said first and second recesses are of dovetail cross section and said key has a double dovetail cross sectional configuration to interlock said support post and said sight rib against vertical separation.

5. The firearm of claim 1 in which said first and second recesses have a dovetail cross section and said key is of double dovetail cross section to securely lock said rib and said anchor post against vertical separation.

6. In combination with a firearm having a barrel, a plurality of support posts rigidly fixed to said barrel in longitudinally spaced relationship, an upwardly extending dovetail projection on each of said mounting posts, a sight rib mounted on said barrel, said sight rib having a groove of dovetail cross section extending the entire length of said rib, said groove being adapted to interlock with the dovetail projections on said mounting posts, an anchor post rigidly secured to said barrel intermediate the ends of said barrel, said anchor post including a pair of longitudinally spaced upwardly extending dovetail projections to interlock with said groove on said rib, a first transverse recess formed in said anchor post between said pair of projections, a second transverse recess formed in said sight rib in aligned relationship with said first transverse recess in said anchor post, said first and second recesses having a dovetail cross section, a key mounted in said transverse recesses to lock said rib against longitudinal movement relative to said barrel, said key having a double dovetail cross section for insertion into said first and second recesses, said key providing a maximum hearing surface to absorb recoil forces transmitted from said barrel to said rib.

References Cited by the Examiner UNITED STATES PATENTS 1,323,149 11/19 Blizard 421 2,496,854 2/50 Crank 42-76 2,620,583 12/52 Simmons 42-76 3,107,450 10/63 Snyder et a1 42-76 FOREIGN PATENTS 146,533 12/03 Germany.

BENJAMIN A. BORCHELT, Primary Examiner. 

1. IN A FIREARM INCLUDING A BARREL, A PLURALITY OF SUPPORT POSTS RIGIDLY SECURED TO SAID BARREL AT LONGITUDINALLY SPACED INTERVALS, A SIGHT RIB MOUNTED ON SAID SUPPORT POSTS FOR LONGITUDINAL SLIDABLE MOVEMENT RELATIVE TO SAID BARREL, AN ANCHOR POST RIGIDLY SECURED TO SAID BARREL INTERMEDIATE THE ENDS OF SAID BARREL, SAID ANCHOR POST HAVING A FIRST RECESS EXTENDING TRANSVERSELY OF SAID BARREL, A CORRESPONDING SECOND RECESS FORMED IN SAID SIGHT RIB IN ALIGNED RELATIONSHIP WITH THE RECESS IN SAID ANCHOR POST AND EXTENDING TRANSVERSELY OF SAID BARREL, A KEY MOUNTED IN SAID RECESSES TO SECURELY LOCK SAID SIGHT RIB AGAINST RELATIVE MOVEMENT LONGITUDINALLY OF SAID BARREL, PIN MEANS EXTENDING THROUGH SAID SIGHT RIB AND INTO SAID KEY TO LOCK SAID KEY SECURELY IN SAID RECESSES, SAID KEY EXTENDING SUBSTANTIALLY ACROSS THE WIDTH OF SAID RIB TO PROVIDE A MAXIMUM BEARING SURFACE TO ABSORB LONGITUDINAL RECOIL FORCES TRANSMITTED FROM THE BARREL TO SAID RIB. 